The process of republishing works isn't simple—and Mr. Kalb's legal training has come in handy. Because it is illegal to scan a book that isn't in the public domain and sell it as an e-book without the author's permission, the couple attempts to track down original authors or their close family members. They split the profits from the e-books with either the authors or their next of kin. Other projects, such as Gutenberg.org, use similar technology but focus on works that are now in the public domain.